A director picking someone else for the role is one person’s taste on one afternoon. Audition again.

Casting is one person’s preference, exercised in a room, under time pressure, against a picture they already had in their head. You might have been excellent and wrong for the part, or right for it and second. None of that is a measurement of whether you can act. It is a single decision made by a single person on a single afternoon.

Put your name down for the next one before the sting wears off, because that is when people quietly stop auditioning. Ask for one piece of feedback if it is offered. Then work on the specific thing and go again.